Amylase resistance and insolubility of ageing costal cartilage in man.

The solubility of human costal cartilage during exhaustive digestion with proteases (van der Korst, Sokoloff, and Miller, 1968) or 5 M guanidine-HCI (Miller, van der Korst, and Sokoloff, 1969) decreases with ageing. These observations stimulated us to investigate the quantitative effect of glycosaminoglycan and protein-degrading enzymes on costal cartilage in regard to age. The first enzyme studied was a-amylase, because crude preparations of this enzyme seem to have a peculiar effect on the intercellular substance of connective tissues, i.e. solubilization of collagen (Steven, 1964) and release of acid glycosaminoglycans (Quintarelli, Dellovo, Balduini, and Castellani, 1969).